Modified colorimetric method for procainamide in plasma.
We describe a modified colorimetric method for determining procainamide in plasma by use of a diazotization and coupling reaction with N-(1-naphthyl)-ethylenediamine dihydrochloride (Marshall's reagent). The sensitivity of the assay is increased twofold over the originally reported colorimetric method, and the lower limit of detection for the assay of a 1.0-ml plasma sample has been decreased to 0.5 mg/liter.
Colorimetry↗